1. Field of the Invention
The present invention relates to a rivet nut tool and, more particularly, to a hand-held rivet nut tool with a replaceable mandrel-driving device that allows replacing a mandrel-driving device on the hand-held rivet nut tool.
2. Description of Related Art
A rivet nut tool is used for mounting a rivet nut on a work piece. With reference to FIG. 12, Taiwan Patent No. 316504 discloses a rivet nut tool with a fixing hole that comprises a body 40 having a base 41 with two handles 42 mounted pivotally and respectively on two sides of the base 41. The handles 42 are mounted pivotally on a driven member 44 respectively through two links 43. A mandrel (not shown on FIG. 12) extends through the driven member 44 and has an external threaded shaft 45 mounted on a head end of the mandrel. A push-and-pull mandrel-driving device 50 is mounted on a tail end of the mandrel and has a mounting tube 51 and a spiral pushing rod 52 mounted in the mounting tube 51. When the rivet nut tool is used, the handles 42 are unfolded to drive the links 43, the driven member 44 and the mandrel, so that the external threaded shaft 45 of the mandrel extends out of a top of the base 41. Then, the spiral pushing rod 52 is firstly pulled and then pushed to rotate the mandrel to screw the external threaded shaft 45 on the head end of the mandrel into a rivet nut 46 that is to be riveted. Further, the handles 42 are folded to drive the mandrel to move along a direction away from the base 41. The moving mandrel drives the external threaded shaft 45 to squeeze and deform the rivet nut 46, so that the rivet nut 46 is riveted on the work piece. Finally, the spiral pushing rod 52 is pulled to remove the external threaded shaft 45 out of the fastened rivet nut 46.
Although the aforementioned push-and-pull mandrel-driving device 50 allows a user to easily and quickly rotate the spiral pushing rod 52 to screw the external threaded shaft 45 into or out of the rivet nut 46, the user can operate the push-and-pull mandrel-driving device 50 only in a sufficient large working space allowing the spiral pushing rod 52 to be pulled and extended to accomplish the riveting process of the rivet nut 46 on the work piece. If the riveting process is executed in a narrow working space, the spiral pushing rod 52 cannot completely extend out due to insufficient working space and therefore cannot accomplish the process for riveting the rivet nut 46 on the work piece. Furthermore, the push-and-pull mandrel-driving device 50 is mounted securely on the body 40 and is not adjustable according to different working spaces, so that using the rivet nut tool in a narrow working space requires a different type of rivet nut tool (for example, a rivet nut tool with a rotational mandrel-driving device).
To overcome the shortcomings, the present invention provides a hand-held rivet nut tool with a replaceable mandrel-driving device to mitigate or obviate the aforementioned problems.